In a statement issued on Saturday, Sadr advised Mursi to “refrain from reopening the Egyptian embassy in Israel,” adding that “one can never trust Israel, neither by good words or by politics.”

He said opening an embassy in the Jewish state “will harm Egypt and the reputation of the Islamists at the same time.”

A letter dated July 19, seemingly written by Egyptian President Mohamed Morsi, sparked controversy in Egypt as the Muslim Brotherhood leader went so far as to refer to Israeli president Shimon Peres as a "great friend."

Morsi’s letter conveyed news of the appointment of Atef Salem Al-Ahl, as Egypt’s new ambassador to Israel.

Al-Ahl, who formally assumed his post on Wednesday, said his country’s new Islamist government remains committed to peace with the Jewish state.

Presenting his credentials Wednesday, Ahl told Israeli President Shimon Peres that Egypt is “committed to all the agreements we signed with Israel and we are also committed to the peace treaty with Israel.”

Tensions between the two were exacerbated last year when Egyptian protesters ransacked offices of the Israeli Embassy in Cairo, dumping Hebrew documents out of a window and trapping six Israeli staff inside for several hours.

Last week, supreme leader of the Muslim Brotherhood, Mohammed Badie, called on Muslims worldwide to defend Jerusalem, saying “Zionists only know the way of force.”

He said that Jews were spreading “corruption” and had slaughtered Muslims and desecrated holy sites. Morsi made no public comments about Badie’s remarks.